Alloy steel



Patented Dec. 26, 1933 ALLOY STEEL Henry A. De Fries, Albany, N. Y.,asslgnor to Ludlum Steel Company, Watervliet, N. Y., a corporation ofNew Jersey No Drawing. Application March 29, 1929 Serial No. 351,119

3 Claims. (Cl. 75-1) My invention relates to improvements in those alloysteels containing chromium in sufllcient quantity to render themsubstantially rustless or stainless, whereby they are more easilyforged,

5 machined, or ground, and whereby their noncorrosive properties areimproved.

Alloy steels containing up to 30% of chromium, and particularly thosecontaining from 12% to are widely used because of their high re- 0sistance to corrosion although considerable difflculty is experienced inthe forging, machining and grinding thereof.

It is well known that a comparatively high sulphur content improves theforgeabllity of ordi- 16 nary steels, but the presence of this elementin so-called stainless steels, in an amount sufllcient to appreciablyaffect the workability thereof, is

extremely detrimental to if not destructive of the veryproperty--stainlessness-which prompts 2 the use of such steels.

I find that alloy steels having a high resistance to corrosion andcontaining up to 30% of chromium may be rendered comparatively easy toforge, machine and grind, and thattheir corrosion resistingcharacteristics 'are not impaired by the presence of from 0.10% to 0.50%of sulphur provided a small amount of copper, say from 0.20% to 1.20%,is also present. The copper not only neutralizes the detrimental effectof the sulphur upon the stainless properties of the steel but materiallyimproves these properties.

The iollowing alloy steel, for example, has high resistance tocorrosion, will flow readily in forging dies, can be easily machined,and can be ground more readily than regular carbon steel:

Carbon 0.07%-0.12% Manganese 0.30%0.50% Silicon 0.30%-0.'l0% o Chromium15.00%-16.00% Copper ,0.50%-0.75% Sulphur 0.25%-0.35% Phosphorus 0.025max.

Inmakingasteelofthischaractenlprefor to'addthecopper andsulphurtogetherinthe formotooppermattaanmtermediateproduct remainderbeing iron".

This is to be understood as including iron and elements such as carbon,silicon, manganese, and phosphorus within the limits usually encounteredin steel making practice.

What I claim is- 1. A steel alloy containing as essential ingredientschromium from 1% to 30%, copper from 0.20% to 1.20%, and sulphur from0.10% to 0.50%; the remainder being iron; said alloy having a resistanceto corrosion comparable to an alloy steel containing chromium in theabove range with sulphur low and under 010%, and being characterized byits easy machinability so and forgeability.

2. A steel alloy containing as essential ingredients chromium from 12%to 20%, copper from 0.20% to 1.20%, and sulphur from 0.10% to 0.50%;'the remainder being iron; said alloy having a resistance to corrosioncomparable to an 35 alloy steel containing chromium in the above rangewith sulphur low and under 0.10%, and being characterized by its easymachinability and forgeability.

3. A steel alloy containing as essential alloying ingredients chromiumfrom 1% to 30%, at least 0.10% of sulphur and at least 0.20% of copper;the total copper and sulphur being under 2% with the copper at leasttwice the sulphur; the remainder being iron; said alloy having aresistance to corrosion comparable to an alloy steel containing chromiumin the above range with sulphur low and under 0.10%. and beingcharacterized by'its easy machineability and forgeablllw marannmms.

